Thanks for all the good feedback guys, some very interesting points, and very helpful.
So there are a few things I can check:
Meter is running up in Miles now rather than KM - Should be known by the current owner!
Background check on the car to confirm mileage when it was exported from Japan. (Thanks for the link, looks like £26 for a check)
Without confirmation of the import mileage the car could have either 100k, 127k or if it was clocked in Japan 162k miles.
Surely this would effect the value of the car, and without this info could I have a problem reselling if I upgrade in a few years time? I don't want to get into that position, but sounds like it might not be too unusual not to have this info. I also need to pay the right prices now so I don't lose money if I resell.
Point taken about maintanance being more important than mileage.
I'm no mechanical expert, I just like driving. So to cover this I will confirm the full service history he has on the car (seems like its been well looked after in his ownership, however I'll ask about the 10 years prior to that) I'm also looking into getting an RAC inspection done, although at £305 I need to determine its going to tell me the important stuff. If anyone knows better people to use that the RAC, and active in the Glasgow area, please should. I'm going to look through the traders section to see if anyone does something like this.